The present invention relates to an apparatus for detecting blockages in the passageways of hydraulic valve castings and more specifically to an apparatus that utilizes the transmission and detection of sound waves to detect such blockages.
Hydraulic valves are manufactured from castings that incorporate a number of passageways. Typically, one of the passageways will accommodate a moving spool that either allows or prohibits communication between a number of other passageways which carry hydraulic fluid to and from pumps, work ports and a hydraulic fluid reservoir. These passageways typically intersect the main spool bore and because of their location, they cannot be visually inspected for blockages.
In the past, these passageways were tested for blockages by utilizing a source of air at high pressure and a blockage was determined by a decrease or deviation in the air flow. This prior art method was not always completely reliable and since it involved the use of very high air pressures, the flow of air through the valve resulted in an extremely high noise level which made it very difficult, if not impossible, for a worker to test valves for a prolonged period of time.
The present invention is directed toward a method and apparatus for testing the passageways of the hydraulic valve in a manner that is reliable and convenient for the worker performing the test.